1. Field of the Invention
The present invention relates to a method for fabricating a vacuum container and a method for fabricating an image-forming apparatus using the vacuum container.
2. Related Background Art
In recent years, applied researches using an electron source constituted by arranging many electron discharge elements on a flat substrate have been extensively performed and for example, development of image-forming apparatuses such as an image display unit and an image recorder has been progressed. Particularly, a thin flat image display unit is watched as a substitute for a cathode-ray-tube display unit because it is space-saving and lightweight. As this type of the flat display unit, a display unit is proposed in which an electron-source substrate (rear plate) obtained by arranging electron discharge elements like a matrix and a face plate having a phosphor disposed so as to face the substrate are formed into an airtight container through a frame. For example, the structure of the display unit is disclosed in the official gazettes of Japanese Patent Application Laid-Open Nos. 08-180821 and 09-82245 and a method for fabricating the airtight container of the above display unit is disclosed in Japanese Patent Application Laid-Open Nos. 09-237571, 2000-090829, and 2000-090830.
In the case of a display unit having the above configuration, a faceplate and a rear plate may be jointed each other by using frit glass. The junction using frit glass is preferable because <1> sufficient airtight joining can be made to constitute a vacuum container and <2> dimensional errors of members (face plate, rear plate, and frame) are allowed because a buffering function is used. The function of the above <2> is particularly requested because a face plate, a rear plate, and a frame member are increased in size as a display unit is increased in size and thereby a shape strain or a dimensional error easily occurs in each of these members. Moreover, as a display unit is increased in size, a spacer may be used in an airtight container as an atmospheric-pressure-resistant structure. Because the spacer is located nearby electron emitting elements arranged at a high density, there were cases where <3> the spacer had a very high aspect ratio in its shape and <4> a film of high resistance (semiconductor film) was formed on the surface of the spacer to prevent an electrification on the surface of the spacer. When a high-temperature (e.g. approx. 400° C.) treatment such as a bonding step using frit is applied to the above spacer, a problem may occur that <5> the spacer is broken due to its shape or <6> characteristics of the antistatic treatment applied to the surface of the spacer may be changed. Moreover, the official gazette of Japanese Patent Application Laid-Open No. 2000-200543 discloses a display unit using a low-temperature jointing material and a display unit in which a low-temperature jointing material and frit glass are mixed. However, when using only a low-temperature jointing material, it is difficult to obtain the functions of the above <1> and <2>. Moreover, when frit glass is mixed, a jointing temperature rises and the problems of the above <5> and <6> occur.